When should multivitamins with iron (Fe) be administered?

When to Give Multivitamin with Iron

Multivitamins with iron should be given routinely to all pregnant women starting when pregnancy is confirmed and continuing for 3 months postpartum, to women of childbearing age (12-49 years) who have inadequate dietary iron intake, and to all patients after bariatric surgery. 1, 2

Pregnancy and Postpartum Period

All pregnant women should receive iron supplementation regardless of anemia status, as dietary intake alone cannot meet the threefold increased iron demands during the second and third trimesters (5.0 mg iron/day). 1

Dosing During Pregnancy

• Standard dose: 30 mg elemental iron daily for routine prevention in all pregnant women 1
• Higher dose: 60-100 mg elemental iron daily for women at increased risk of iron deficiency (those with previous iron-deficiency anemia, high parity, intrauterine device use, or low dietary iron intake) 1
• Low-dose regimens (30 mg/day) are as effective as higher doses (60-120 mg/day) for preventing iron-deficiency anemia and cause fewer gastrointestinal side effects 1

Postpartum Continuation

• Continue iron supplementation for at least 3 months after delivery in all postpartum women to replenish maternal stores depleted during pregnancy 2
• Women at high risk for postpartum anemia should be screened at 4-6 weeks postpartum and may require extended supplementation beyond 3 months 2
• All breastfeeding women should continue comprehensive multivitamin-mineral supplementation throughout lactation to meet increased nutritional demands 2

Women of Childbearing Age (Non-Pregnant)

Multivitamins with iron are indicated for adolescent girls and women aged 12-49 years, as only one-fourth meet the recommended dietary allowance for iron through diet alone, and 11% have iron deficiency. 1

High-Risk Groups Requiring Supplementation

• Women with heavy menstrual bleeding 1
• Women with previous iron-deficiency anemia 1
• Women using intrauterine devices (associated with increased menstrual blood loss) 1
• Women with high parity 1
• Women with low dietary iron intake 1

Note: Oral contraceptive use decreases iron deficiency risk and may not require routine supplementation. 1

Post-Bariatric Surgery Patients

All bariatric surgery patients require lifelong multivitamin supplementation with iron, with specific dosing based on surgical procedure. 1

Routine Supplementation Regimens

• Two adult multivitamin-mineral supplements daily containing iron, folic acid, zinc, copper, selenium, and thiamin (200% of RDA) after Roux-en-Y gastric bypass (RYGB), sleeve gastrectomy (LSG), or biliopancreatic diversion (BPD) 1
• One multivitamin daily after laparoscopic adjustable gastric banding (LAGB) 1
• Additional elemental iron: 45-60 mg daily from multivitamin and supplements (after LAGB, only if dietary intake is insufficient) 1

Treatment of Deficiency

• 150-200 mg elemental iron daily for documented iron deficiency 1
• Women of childbearing age or at increased risk should consume 50-100 mg elemental iron daily 1

Men and Postmenopausal Women

Routine multivitamins with iron are NOT recommended for men or postmenopausal women, as iron-deficiency anemia is uncommon (≤2%) in these populations. 1

When to Investigate Rather Than Supplement

• In men and postmenopausal women with anemia, the primary causes are chronic disease, inflammatory conditions, or gastrointestinal bleeding (62% have GI lesions such as ulcers or tumors) 1
• Do not assume low iron intake is the cause—investigate for underlying pathology before supplementing 1

Critical Timing and Administration Considerations

Separation from Calcium

• Separate iron and calcium supplements by at least 1-2 hours, as calcium inhibits iron absorption 2
• Single calcium doses should not exceed 600 mg 1

Monitoring Schedule

• During pregnancy: Screen for anemia at first prenatal visit, again at 24-28 weeks, and in third trimester 1
• Postpartum/breastfeeding: Check full blood count, serum ferritin, iron studies every 3 months 2
• Post-bariatric surgery: Monitor iron studies every 3 months initially, then every 6 months long-term 2

Response Assessment

• Expect hemoglobin rise of at least 10 g/L after 2 weeks of daily oral iron therapy 1
• Failure to achieve this response suggests non-compliance, malabsorption, continued bleeding, or concurrent deficiencies requiring investigation 1

Common Pitfalls to Avoid

• Never discontinue supplementation immediately postpartum, as nutritional demands remain elevated during breastfeeding and maternal stores are depleted 2
• Do not prescribe iron supplements to men or postmenopausal women without investigating for underlying pathology first 1
• Avoid high-dose iron regimens (>60 mg daily) in routine pregnancy supplementation, as they increase side effects without improving outcomes and may negatively affect mineral absorption 1, 3
• Do not rely solely on dietary intake to meet iron needs during pregnancy, postpartum, or after bariatric surgery, as dietary sources are insufficient even with optimal nutrition 2